Treatment of hydrocarbon oils



Patented May 29, 1934 ETD STAES' ATENT? rric TREATMENT F HYDROCARBON OILS No Drawing. Application August 10, 1931, Serial No. 556,321

4 Claims.

This invention relates to the treatment of hydrocarbon oils, and refers more particularly to the treatment of petroleum hydrocarbons primarily for the purpose of desulfurizing them. In

5 one of its specific aspects the invention relates to the treatment of petroleum distillates, especially those produced by cracking relatively higher boiling hydrocarbons into lower boiling hydrocarlocus.

The problem of the removal of sulfur in its manifold forms from petroleum distillates is one of long standing in the petroleum industry. Present day specifications for the sulfur content of motor fuels demand a product which is very low in sulfur content, e. g., approximately 0.1%.

The presence of too much sulfur of any type in petroleum distillates is objectionable because of the possibility of forming sulfuric acid as an ultimate product in the combustion of the motor fuel resulting in corrosion of the crank case and other parts of the motor.

Heretofo-re, no adequate process has been developed which is applicable to the desulfurization of the various kinds of petroleum distillates requiring treatment, particularly those resulting from cracking.

In ordinary refining practice the kinds and amounts of reagents used are suitable for the removal of some of the types of sulfur compounds present in petroleum distillates, but investigations have shown that the most refractory types of sulfur compounds are present in the largest proportion in high sulfur distillates; for example,

elementary sulfur, mercaptans, sulfides and disulfides are relatively easy to remove, whereas the thicphene-like and other so-called residual sulfur compounds are very refractory in this respect. The most difiicult types of distillate to treat from the viewpoint of desulfurization result 49 from the cracking of higher boiling hydrocarbons containing a relatively high percentage of sulfur, the compounds of which are apparently rearranged to form sulfur compounds which cannot be readily removed by treatment with the most -c0mm0nly used reagents such as sulfuric acid.

In one of its specific aspects the invention comprises subjecting hydrocarbon oils to heat treatment under atmospheric or superatmospheric pressure, depending on other conditions with 50 hydrogen while in contact with a catalytic material comprising charcoal and particularly activated charcoals and also in the presence of phosgene or carbonyl chloride. Phosgene is variously known as carbon oxychloride, carbonyl dichloride and chlorocarbonic acid. The active charcoals employed may be derived from many sources such as activated chars from cocoanut shells, wood, peat, lignite and similar chars. Hydrogen-containing gases, such as cracked gases, may also be employed, although not as eifectively as hydrogen alone.

Hydrogen has been employed heretofore for the removal of sulfur, but the conditions required for such treatment have made the cost of equipment and operation practically prohibitive; for example, pressures of approximately 3,000 pounds per square inch have been employed. In the process of the present invention satisfactory results have been obtained at very greatly reduced pressures for corresponding temperatures, rendering the process both economical and practical.

In the operation of the process of the present invention the hydrocarbons to be treated are passed at elevated temperatures and preferably in heated vaporous condition together with hydrogen and phosgene over the catalyst comprising an activated charcoal. The hydrogen and phosgene are introduced directly into the hydrocarbons undergoing treatment.

The vapors leaving the reaction chamber, dephlegmator, fractionator or other elements of a cracking process may be passed together with hydrogen and phosgene over a body or mass of charcoal. Similarly, the vapors leaving the evaporator of a conventional pipe still or a shell still may be likewise treated, preferably superheating them to the required conditions for treatment; or,- the condensates from such operations may be heated at atmospheric or superatmospheric pressures and the vapors resulting therefrom treated With hydrogen and phosgene while in contact with the charcoal. The process may be adapted to: operate in conjunction with any concurrently operating process wherein hydrocarbons are in a vapor condition or are subjected to vaporization.

While the conditions of treatment are generally much milder than those employed in ordinary hydrogenation operations they may vary over a wide range; for example, temperatures varying from 500- F. to 1,000 F and pressures varying from atmospheric to 1,500 pounds and upward may be employed. Generally, the temperature may be increased somewhat as the pressure is decreased.

As examples of the conditions suitable for the operation of the process of my invention and the results obtained thereby, when a California cracked distillate containing approximately 0.7% sulfur is treated at a temperature of approximately 840 F. at substantially atmospheric pressure employing approximately 6% of hydrogen by weight of the oil undergoing treatment, passing the mixture of hydrocarbons, hydrogen and phosgene over activated charcoal, a reduction to less than 0.1% of sulfur may be obtained. Approximately 1% of phosgene based on the hydrocarbons treated is employed. Also, when a California cracked distillate containing 0.45% of sulfur was treated with approximately 5% by weight of hydrogen at 850 F. and atmospheric pressure in contact with active charcoal the sulfur content was reduced to 0.05%. The gasoline product was water white, of good odor and stable color and of 10W gum content. At 675 F. with suitable time factor and excess hydrogen hydrocarbons containing in excess of 0.5% sulfur may be reduced to approximately 0.05% sulfur by the process of the present invention.

Good results may be obtained with other types of hydrocarbon mixtures of high sulfur content, for example, those from Mexican, Venezuelan and other crude oils.

The charcoal may be reactivated for re-use by steam treatment or other activating treatments in accordance with the usual practise.

The conditions of treatment and amounts of reagents shown in the above examples or otherwise cited herein are for illustrative purposes only and are not to be construed as limitations upon the process or in general upon the spirit and broad scope of the invention.

I claim as my invention:

1. A process of desulfurizing hydrocarbons, which comprises reacting sulfur compounds contained in the oil with hydrogen at an elevated temperature in the presence of phosgene while in contact with charcoal.

2. A process of desulfurizing hydrocarbons, which comprises subjecting said hydrocarbons to the action of hydrogen at an elevated temperature between 500 F. and 1000 F. in the presence of phosgene while in contact with activated charcoal.

3. A process of desulfurizing cracked hydrocarbon distillates, which comprises subjecting said distillate in heated vaporous condition to the action of hydrogen at a temperature in excess of 650 F. at substantially atmospheric pressure in the presence of phosgene while in contact with activated charcoal.

4. A process for desulfurizing cracked hydrocarbon distillate which comprises passing the vapors thereof in admixture with hydrogen and phosgene and at a temperature in excess of 500 F. over activated charcoal.

GUSTAV EGLOFF. 

